struct lhdfs_data_block load_block(int fd, off_t address){
	struct lhdfs_data_block db_block;
	if(address < 0){
		printf("argument address error!\n");
		return -1;
	}
	if(8196 != pread(fd,&db_block,8196,address)){
		printf("load_block:pread error!\n");
		return -1;
	}
	return db_block;
}


